Many piping and plumbing process systems require that pipes, tubing, and fittings be attached by threaded fasteners. Screw threads on nuts or on fittings can be damaged in several ways. If the threads cannot be repaired, usually the nut, pipe, or tubing is discarded or has to be spliced. A problem with attempting to repair threads is the inability to maintain the tap or die coaxially aligned with the nut or fitting being repaired. If the repair is performed with the tap or die at an angle, the screw threads will be misaligned and fittings being joined may not function properly. Compression fittings are commonplace. In a compression system, a nut with a hole in the center through which a tube passes is used to connect the tube to a fitting. A ferrule, also with a hole in the center, is placed on the end of the tube and in front of the nut. When the nut is tightened against a fitting to connect the tube to the fitting, the ferrule can be compressed against tube material, thus deforming the tube and helping to create a seal. During the threading process, the threads on the nut or the fitting may be damaged due to an initial misalignment. A problem arises when repairing a captured nut on a tube because the tube renders the nut inaccessible.
Accordingly, it would be useful to provide a tap and die device that can repair external and internal screw threads to avoid having to discard or splice materials. It would further be advantageous to provide a tap and die device that can coaxially align a workpiece needing to be repaired with the tap or die. It would further be advantageous to repair a nut while captured on a tube.